Here’s a picture of the factory linkage for a ’57 Ford dual quad setup.  You’ll not be over-carbureted with a pair of Holley Teapots on the flattie.  The vacuum secondaries will be very forgiving in insuring that the engine receives only the cfm it needs.  If you would like the Teapot secondaries to open more correctly, then you’ll need to replace the factory silver secondary springs with the long yellow springs that come in the Holley spring kits for the 4150/4160 Holley carbs.